Sperm storage and viability within females of Euscepes postfasciatus: Effect of irradiation on sperm abundance and viability within female

Irradiation has been widely used in suppression or eradication programs that use the sterile insect technique (SIT) or in studying sperm competition. Although it is well known that irradiation has negative impacts on reproductive (sperm) cells, previous studies have assumed that sperm from irradiated males behave identically to normal sperm in the female reproductive tract after mating. In this study, we used the West Indian sweetpotato weevil Euscepes postfasciatus to investigate the effect of irradiation on the abundance and viability of sperm in female spermatheca for 14 days after copulation. The abundance of sperm in females did not change throughout the experimental period, and sperm viability gradually decreased regardless of irradiation. In this weevil, irradiated sperm appear to behave identically to normal sperm in females for 14 days following irradiation/copulation. Therefore, the effect of irradiation on sperm viability within the female spermatheca is considered to be insignificant.     

苜蓿国际发展态势分析

苜蓿是草食动物的优质饲草, 被誉为“牧草之王”。发展苜蓿产业对提升我国草食畜牧业具有重要意义。该研究采用定性调研与定量分析相结合的方法, 从创新链角度, 研究了全球苜蓿科技产出、代表性国家苜蓿产业格局和全球苜蓿市场贸易等状况及我国苜蓿产业存在的问题, 旨在为我国苜蓿产业发展提供参考。分析发现, 美国是全球最重要的苜蓿生产国, 在苜蓿基础研究、技术开发、品种培育和商业化种植等方面均具有很强的优势, 引领了全球苜蓿产业的发展。欧美等跨国企业掌控着全球苜蓿产业链的各个关键环节, 是苜蓿产品的主要出口市场, 而亚洲苜蓿产品消费缺口最大。近10年来, 我国在苜蓿科技领域表现活跃, 科技成果产出呈快速增长趋势, 但在成果数量和影响力方面与欧美国家差距明显, 且苜蓿育种进程缓慢, 优质苜蓿产品对外依存度仍然较高。综合来看, 我国应持续加大苜蓿的研发力度和科技投入, 推进苜蓿产业化发展, 提升苜蓿产品的自给率, 保障草食畜牧业健康、稳定发展。     

Labile pool of cadmium in sludge-treated soils

The labile pool of cadmium in sludge-treated soils was determined by application of isotopic dilution principle under laboratory and green house conditions using moong (Phaseolus aureus L.) as test crop. The laboratory indices like isotopic distribution coefficient (Kd) of 115Cd in 0.1 M CaCl2, labile pool (LP) of Cd in DTPA–CaCl2–Na acetate (adjusted to pH 5.0, 6.0 and 7.0) and supply parameter (SP) using Kd as intensity and LP as capacity factor of Cd in soils, were computed to compare these values with actual uptake of Cd by the crop to test them as indices of Cd availability. The path-ways of transfer of soil Cd from the discrete chemical pools to plants were also computed. The LP (pH 7.0) and the SP were significantly correlated with the concentration of Cd in plants and its uptake by the crop. They are, therefore, good indices of Cd availability in sludge treated vertisol soils and can be used as reference indices for standarization of chemical extractants. The water soluble + exchangeable Cd and the 0.05 M EDTA extractable Cd were observed to be the two major chemical pools of Cd in soils responsible for supply of this element to plants. As substantial part of 0.1 M Na4P2O7 extractable Cd applied to the soils remains in same form, they are not transfered into the food chain. The amounts of soil Cd extracted by DTPA–CaCl2–TEA (pH 7.3), EDTA–NH4OAC (pH 7.3) and Mg(NO3)2 (pH 6.0) were significantly correlated with concentration of Cd in plants and with uptake of Cd by moong crop.     

Muon spin resonance of radicals on surfaces

Polarized positive muons are incorporated as spin labels in organic free radicals adsorbed on large-area surfaces. Two muon spin resonance techniques are introduced which allow the detection of the muonanted species, either in transverse or near avoided crossings of energy levels in longitudinal magnetic fields. The radicals are characterized by their hyperfine interactions, and dynamic information is obtained from the extent of averaging of the hyperfine anisotropy. Because of the high spin polarization the method is extremely sensitive and allows the study of radicals at concentrations down to a single radical in the sample at a given time, and therefore under conditions of high mobility where conventional techniques often fail due to radical termination reactions.     

Genetic sexing strains in medfly,Ceratitis capitata,sterile insect technique programmes

The introduction of genetic sexing strains (GSS) into medfly, Ceratitis capitata(Wiedemann), sterile insect technique (SIT) programmes started in 1994 and it was accompanied by extensive evaluation of the strains both in field cages and in open field situations. Two male-linked translocation systems, one based on pupal colour, wp, and the other based on temperature sensitivity, tsl, have been used in medfly SIT programmes and they have quite different impacts on mass rearing strategy. In strains based on tsl, female zygotes are killed using high temperature and for wpstrains, female and male pupae are separated based on their colour. In all these systems the colony females are homozygous for the mutation requiring that the mutation is not too deleterious and the males are also semi-sterile due to the presence of a male-linked translocation. Managing strain stability during large-scale mass rearing has presented some problems that have been essentially solved by selecting particular translocations for GSS and by the introduction of a filter rearing system (FRS). The FRS operates by removing from the colony any recombinant individuals that threaten the integrity of the strain. The use of GSS opens up the possibility of using the SIT for suppression as opposed to eradication and different radiation strategies can be considered. Some of the many field trials of the strains that were carried out before the strains were introduced into operational programmes are reviewed and an overview is given of their current use.     

Sexual behaviour of Anastrepha obliqua (Macquart) (Diptera: Tephritidae): Do laboratory domestication conditions influence male courtship behaviour?

We analysed the influence of laboratory domestication, under relaxed conditions, on the courtship behaviour of the fruit fly species Anastrepha obliqua, an important agricultural pest. We compared the temporal patterns of pheromone emission (Calling behaviour) and the frequencies and sequences of the courtship behavioural units of males of a laboratory lineage and a wild lineage. Our results indicated similarities in the temporal behavioural patterns of calling, the durations of their behavioural sequences, the final sequences of courtships resulting in copulation, of wild and laboratory males. Differences, however, were observed between the two populations in terms of the frequencies of the behavioural units executed and the initial sequence of courtship. Differences were noted in the presence or absence of some behavioural units within the courtship behavioural repertoires of the laboratory-reared and wild. The wild males did not show units such as Alignment, Contact, Fighting and Marking Leaf that were observed in the laboratory males' courtship behaviour under laboratory conditions; on the other hand, laboratory males did not show the Abdominal movements and Oscillation observed in the courtship behaviour of wild males. The rearing of A. obliqua males under relaxed conditions in the laboratory provides an environment adequate for the preservation of behavioural characteristics relevant to the successful mating, such as Movement, Arrowhead 1, and Attempt, and in temporal patterns of pheromone emission.     

Novel complex hydrogels based on N-carboxyethyl chitosan and quaternized chitosan and their controlled in vitro protein release property

A novel pH-responsive hydrogel (CHC) composed of N-carboxyethyl chitosan (CEC) and N-[(2-hydroxy-3-trimethylammonium) propyl] chitosan chloride (HTCC) was synthesized by the redox polymerization technique. Turbidimetric titrations were used to determine the stoichiometric ratio of these two chitosan derivatives. The hydrogel was characterized by FT-IR, thermal gravimetric analysis (TGA), X-ray diffractometry (XRD), and scanning electron microscopy (SEM). The dynamic transport of water showed that the hydrogel reached equilibrium within 48 h. The swelling ratio of CHC hydrogel depended significantly on the pH of the buffer solution. The performance of the CHC as a matrix for the controlled release of BSA was investigated. It was found that the release behavior was determined by pH value of the medium as well as the intermolecular interaction between BSA and the hydrogels.